Method for optimizing control of a production unit

Abstract

The octane number of a product is directly determined from its near infrared (NIR) absorption spectrum in the wave number spectral range of from 6667 to 3840 centimeter -1 . A number (n) of frequencies is selected within this range, and the (n) absorbance values are correlated with the octane number by using a multivariate regression analysis.

We claim: 
     
       1. In a process for optimizing the control of a production unit for making an internal combustion engine fuel product or base stock with a desired octane number, the improvement which comprises: (a) determining the octane number of said fuel product or base stock by (i) measuring the near infrared absorption of said fuel product or base stock within the wave number spectral range 4800-4000 cm -1 , and (ii) directly correlating by means of multivariate regression analysis the (n) absorbance values obtained with the octane number of said product or base stock; and (b) employing said determined octane number to control and optimize the process to produce said desired octane number. 
     
     
       2. The process according to claim 1 wherein (n) is in the range 1-200. 
     
     
       3. The process according to claim 2 wherein (n) is in the range 1-30. 
     
     
       4. The process according to claim 3 wherein the (n) frequencies used are selected from those defined by the following: F 1  =4670 cm -1     F 2  =4640 cm -1     F 3  =4615 cm -1     F 4  =4585 cm -1     F 5  =4485 cm -1     F 6  =4385 cm -1     F 7  =4332 cm -1     F 8  =4305 cm -1     F 9  =4260 cm -1     F 10  =4210 cm -1     F 11  =4170 cm -1     F 13  =4100 cm -1     F 14  =4060 cm -1     F 15  =4040 cm -1     
     
     
       5. The process according to claim 1 wherein the correlations are not affected by a susceptibility of the product to lead alkyls. 
     
     
       6. The process according to claim 1 wherein the product is a gasoline. 
     
     
       7. The process according to claim 7 wherein the gasoline contains lead alkyls. 
     
     
       8. The process according to claim 6 whereof the gasoline contains oxygenated compounds. 
     
     
       9. The process according to claim 1 wherein at least one of the following octane numbers are determined simultaneously: clear research, clear motor, leaded research and leaded motor. 
     
     
       10. A process as claimed in claim 1, wherein the production unit is selected from the group consisting of reforming, thermal, and catalytic cracking units.